Your 1987 300 sdl Mercedes Benz will surge and has a loss off power at low speeds what could be causing this?

Answer 1

There are two possibilities with this problem. There is a small silver relay next to the fuse box toward the passenger side. It sits next to the A/C relay. You will recognize it because it has a plastic cover with a 10 amp fuse in the top. Either this relay is going bad or.... check the connection of the two wires coming from the tach sending unit (down where the tranny connects to the motor) They are brown and white. They run up to a connector on the side of the intake manifold and then to the injector pump. These wires tend to get frayed and short after a period of time. It looks like they are connected, but open the connector casing and inspect the wires where they are soldered to the connector pins. A short in this connection will cause the A/C to stop working, the idle will drop to about 450 rpm, the tach wil stop working or work intermittently, and the ABS will not function. If you find a short, you can simply splice the wires together and bypass the connectors, or purchase a new tach sending unit to replace the connector altogether.